Information retrieval in the form of discs having coded data distributed in a circular or spiral pattern has been available in various forms for many years. Early forms of musical reproduction equipment, for example, used discs with either holes or protuberances to pluck an arry of strings or vibrating posts to produce music. Early displays of moving pictures operated by a rotation of a disc bearing consecutive images on a periphery. The most common form of storing reproductions of music performances which has been in use for about 100 years, is the phonograph record which uses a spiral pattern of grooves having vertical and horizontal modulations to generate signals which can be converted to sound.
With the introduction of the laser to industry, a new information storage system has been developed which comprises a disc having circular or spiral patterns of depressions or protuberances which would disturb, reflect or refract incident or transmitted light patterns. These information storing discs, often used for storage of audio/visual information and generally referred to as video discs, are well known in the art. Such U.S. patents as U.S. Pat. Nos. 3,658,954; 3,795,534; 3,798,134; 3,855,426; 3,901,994; 4,124,672; 4,126,716; and 4,130,620 show various constructions, compositions, and processes for forming video discs.
U.S. Pat. No. 4,126,726 also shows the use of photocurable laquers to form an image carrying surface and to provide a protective cover over the information carrying surface when a reflective metal film is used. No information whatsoever with regard to the nature and properties of the radiation curable layer is provided. In all instances the reflective metal coatings are provided to the element after the information is applied to its surface.